Cause

an individual backup image file was deleted from the image location, or file level corruption occurred some time after the backup

backups may be created in a corrupt state due to problem with backup Image Location (for example, disk error or unstable network connection)

the backup is not corrupt, but a read IO error occurs during the verify or recovery process

a system resource issue in Windows may cause verify/recovery process to fail

Solution

Perform the following steps to isolate the problem: -

1) attempt to verify the backup again using Verify Images page in Kaseya UI, in case there was a temporary problem with access to the image location

2) if the problem occurs only in the current backup set, force a new full backup by re-applying the Image Password on the affected backup agent

- password does not need to be changed, just reapplying the same password again will force the next backup to be non-synthetic full backup

3) if the problem still persists in the new set, copy the whole of the current backup set to another location. If the image location is a LAN share, copy to a locally attached drive. Attempt to verify from that location using the Kaseya Backup Local UI or Acronis Management Console ("validate" function). If this is successful, there is a read IO problem affecting the original image location

4) if the problem still persists after copying the set, create a new backup directly in that location and test if this can be verified. If this is successful, there is a disk error or network problem causing corruption of backups created in the original image location

If backups created in multiple locations cannot be verified: -

5) attempt to verify the backup from a different backup agent machine

6) boot from the Acronis "Universal Restore" CD and test the following: -

- "validate" existing backups. If successful, there is a problem in Windows affecting the verify/recovery process.

- take a new backup from the boot CD, and check if that can be validated. If successful, there is a problem in Windows causing backup to be created in corrupt state.

If backups created from the recovery CD cannot be verified, there may be a hardware fault.

If the problem is specific to a network-based Image Location: -

check network adapter drivers are up-to-date on the source machine and the server or NAS device hosting the file share

test the backup without any on-access AV software running on the server hosting the LAN share

if the LAN share is on a computer running a Windows desktop OS (such as Windows XP or Windows 7), the problem may be caused by the concurrent connection limitations of this operating system. Try changing the auto-disconnect timeout as described here -http://support.microsoft.com/kb/314882 (!) we do not recommend using a workstation OS or “workstation class” hardware as the image location for large or multiple backups

to further isolate the issue, test backing up to a network location on a different file server / NAS device

If the problem is specific to Image Location on a locally attached drive: -